Management of Low-Grade Appendiceal Mucinous Neoplasms (LAMN): An International Survey of Surgeons Performing CRS and HIPEC

Background: Low-grade appendiceal mucinous neoplasms (LAMN) are commonly managed by community surgeons at diagnosis. There is variability in the treatment of LAMN, both by community and specialist providers. We assessed current management practices for LAMN across surgeons with expertise in peritoneal surface malignancies (PSM). Methods: An online survey was sent to 106 international surgeons specializing in PSM. The survey assessed demographics, favored pre-referral management, and definitive management practices for LAMN. Results: The response rate was 40% (67% USA, 33% international). Respondents had performed a median of 18 (interquartile range [IQR] 7.75–29) HIPEC cases in the last year, of which 10 (IQR 4–20) were for LAMN. Ninety-three percent reported more than half of LAMN referrals had already undergone surgery—an estimated 50% appendectomy and 20% right hemicolectomy (RH). No surgeon respondents supported performing right hemicolectomy before referral. For LAMN confined to the appendix, 86% of respondents would definitively treat with appendectomy. In the presence of mucinous implants, 24% would observe after appendectomy and 76% would proceed with HIPEC. All would perform HIPEC if implants contained tumor cells. When LAMN involved the appendiceal base, 67% of respondents would proceed with partial cecectomy, while 33% favored RH. Conclusions: Pre-referral management of LAMN is not standardized and 20% of patients were referred to a surgeon who performs CRS/HIPEC after a right hemicolectomy that would not have been recommended. Management of LAMN by surgeons who treat PSM is also variable. Long-term data and identification of prognostic features are necessary to generate consensus on the optimal management of these complex patients.